"My whole world and my whole life has been: This is what happens. This is how power dynamics play out," said Sanford-Kelly, a Bethesda, Maryland, resident who's now 14.

The middle-schooler considered what she could do to prevent sexual assault and landed on the concept of sexual consent education. She started locally, with help from her friends and her mother, Del. Ariana Kelly, who represents a portion of Montgomery County. Eventually, their efforts had a greater impact.

Sanford-Kelly said her teachers at North Bethesda Middle School used an analogy about offering someone tea to teach about consent. Someone might want tea on Monday but not on Tuesday. They might want tea with honey but not sugar. Just as you wouldn't force someone to drink a cup of tea if they didn't want to, you wouldn't force them to have sex, the teen said she was taught.

The lessons were "really accessible" and "stick in your mind," Sanford-Kelly said.

She, her mother and her friends first wrote a bill about consent education and took it to the Montgomery County Delegation in December 2016. Sanford-Kelly and her friends testified for the passage of the bill.

After the teens presented the idea at the local level, they decided to think bigger.

Despite the failed statewide attempt, Montgomery County and Baltimore City schools voluntarily implemented the bill in 2017.

When the #MeToo movement took hold in fall 2017, Kelly and the teens gained a second wave of support at the state level. In early 2018, their bill was approved in the House of Delegates and State Senate. Then, Gov. Larry Hogan signed consent education into law in May 2018.

Irene van der Zande is the executive director and founder of Kidpower, a nonprofit that works with educators to teach personal safety to students of all ages. The group has collaborated with schools in several states and designed curricula to teach and reinforce skills for students to carry with them long after they leave the classroom.